TRANSFER CASE WON'T SHIFT

1998 Isuzu Trooper

Transmission problem
1998 Isuzu Trooper 6 cyl Four Wheel Drive Manual

The transfer case shifter is stuck in 4 wheel High when you push the on the fly button in it will go into 4 wheel high but I can" t use 4 wheel low also the green 4 wheel engagement light stays lite and flashing.

RETRIAL OPERATION
After switch signal is received by motor actuator, shift change begins. However, if shifting cannot be completed due to cold temperatures or high speed operation, system will attempt switching again after 2 seconds if shift change is not completed. Motor actuator will reverse its rotation for 1.2 seconds, then try to switch again. This process will be repeated up to 3 times. The 4WD indicator light will blink rapidly to indicate shift switching is being attempted.

Something is not functioning causing the shifting to be unable to complete. Check the vacuum hoses for leakages and VSV operations.